This invention belongs to the field of agricultural chemistry, and provides to the art new compounds useful for protecting plants from, and reducing the adverse effects of, foliar phytopathogens. The protection of plants from such phytopathogens is of paramount importance in agriculture. Nearly every ornamental and crop plant is injured by diseases caused by foliar phytopathogens. Many important crops cannot be economically raised without chemically protecting the plant from such phytopathogens. Some of the earliest achievements of agricultural chemistry were in the field of plant protection, and the art continues to search vigorously for new and improved plant protective agents.
Some prior publications are important to an understanding of the background of this invention. Dreikorn, U.S. Pat. Nos. 3,764,681 and 3,839,569, disclosed the fungicidal efficacy of tetrazolo[1,5-a]quinolines, dihydrotetrazolo[1,5-a]quinolines and s-triazolo[4,3-a]quinolines. Belgian Pat. No. 803,098 and West German Offenlegungsschrift No. 2,249,350 disclosed fungicidal use of certain imidazoquinoxalines.
The hydrogenation of multiple-fused-ring systems has been illustrated by, for example, de Ruiter, U.S. Pat. No. 3,775,417, by Sulkowski, U.S. Pat. No. 3,624,093, and by Reimlinger, U.S. Pat. No. 3,639,406. The reader is also referred to Huisgen, Justus Leibigs Ann. Chem. 610, 57-66 (1957), C.A. 52, 9125(d) (1958), who described dihydrotetrazoloquinolines and related compounds.
British Pat. No. 1,001,067 shows 4,5-dihydrotetrazoloquinolines, used as photographic chemicals, U.S. Pat. No. 3,835,137, of Wagner, shows dihydrotetrazoloquinazolines to be useful fibrinolytic agents.